Northern Jarrah Forest – Is There a Mesopredator Release Effect?
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Invasive Animals Cooperative Research Centre Uptake of Products and Strategies Program: Project:10.U.1 Western Australian Demonstration Site Subproject 2: Introduced predator control and sustained fauna recovery in south- west Western Australia. The importance of fox, cat and native predator interactions to sustained fauna recovery in the northern jarrah forest – is there a mesopredator release effect? Progress Report at 30 June 2008 Paul de Tores, Duncan Sutherland, Al Glen, Rob Hill, Lenny Bloomfield, Sean Garretson, Lauren Strümpher, Deb Feeniks, Helen Darby, Sheree Mammone, Jennyffer Cruz and Gillian Bryant Not for citation without discussion with the authors Contents 1 The project team, collaborators and volunteers .............................................. 1 2 Overview and background ................................................................................. 5 3 The northern jarrah forest predator interaction project .................................. 7 4 Objectives and hypotheses................................................................................ 9 5 Methodology ...................................................................................................... 16 5.1 The baiting treatments – spatial and temporal design ....................................16 5.2 Trials to assess non-target uptake of the cat bait, Eradicat............................18 5.3 Indices of Activity and estimates of density - sandplots..................................18 5.3.1 Fox and cat indices and density estimates....................................................... 18 5.3.2 Indices of activity for varanids and chuditch..................................................... 22 5.4 Molecular analyses .........................................................................................22 5.4.1 Epithelial scrapings from predator scats........................................................... 22 5.4.2 Hair traps .......................................................................................................... 22 5.5 Fox and cat dietary analysis ...........................................................................22 5.6 Fox and cat use of the landscape – trapping and satellite telemetry..............22 5.7 Native predators .............................................................................................23 5.7.1 Chuditch density estimates, survivorship and habitat use................................ 23 5.7.2 Varanid density estimates, survivorship and habitat use ................................. 23 5.7.3 Python survivorship, behaviour, habitat use and health................................... 26 Background and hypotheses ............................................................................ 26 Capture of pythons, implanting of radio-telemetry transmitters and radio- telemetry monitoring ......................................................................................... 26 5.8 Availability of prey species – trapping webs ...................................................26 5.9 Habitat assessment of trapping webs.............................................................27 5.10 Brushtail possum density estimates, survivorship, diet, behaviour, habitat use and health .......................................................................................................29 5.10.1 Diet.................................................................................................................... 29 5.10.2 Effect of resource availability and predation on density of western brushtail possum populations.......................................................................................... 29 Trapping............................................................................................................ 30 Food availability ................................................................................................ 30 Den availability.................................................................................................. 31 Predation .......................................................................................................... 31 5.10.3 Effects of resource availability and predation on western brushtail possum population parameters...................................................................................... 31 5.10.4 Disease............................................................................................................. 32 5.10.5 Behavioural responses to predation................................................................. 32 -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The importance of fox, cat and native predator interactions to sustained fauna recovery in the northern jarrah forest – is there a mesopredator release effect? June 2008 progress report to the Invasive Animals Cooperative Research Centre Page i Contents (… cont.) 6 Progress to date ................................................................................................ 33 6.1 The baiting treatments – spatial and temporal design ....................................33 6.2 Trials to assess non-target uptake of the cat bait, Eradicat............................33 6.3 Indices of activity and estimates of density - Sandplots .................................33 6.3.1 Fox and cat indices of activity and estimates of density................................... 33 6.3.2 Indices of activity for varanids and chuditch..................................................... 39 6.4 Molecular analyses .........................................................................................41 6.4.1 Epithelial scrapings from predator scats........................................................... 41 6.4.2 Hair traps .......................................................................................................... 41 6.5 Fox and cat dietary analysis ...........................................................................41 6.6 Fox and cat use of the landscape – trapping and satellite telemetry..............41 6.7 Native predators .............................................................................................43 6.7.1 Chuditch density estimates, survivorship and habitat use................................ 43 Mark-recapture study........................................................................................ 43 Home ranges and habitat use .......................................................................... 44 Diet.................................................................................................................... 44 6.7.2 Varanid density estimates, survivorship and habitat use ................................. 45 Mark-recapture study........................................................................................ 45 Home range and habitat use ............................................................................ 47 Temporal activity............................................................................................... 49 Diet.................................................................................................................... 50 6.7.3 Python survivorship, behaviour, habitat use and health................................... 50 Sample size ...................................................................................................... 50 Radio telemetry................................................................................................. 50 6.8 Availability of prey species – trapping webs ...................................................53 6.9 Habitat assessment of trapping webs.............................................................53 6.10 Brushtail possum density estimates, survivorship, behaviour, habitat use and health ..............................................................................................................54 6.10.1 Diet.................................................................................................................... 54 6.10.2 Effect of resource availability and predation on density of western brushtail possum populations.......................................................................................... 54 6.10.3 Effects of resource availability and predation on western brushtail possum population parameters...................................................................................... 54 6.10.4 Disease............................................................................................................. 54 6.10.5 Behavioural responses to predation................................................................. 55 7 Publications and presentations ....................................................................... 59 7.1 Publications (published or in review) ..............................................................59 7.2 Publications (in prep) ......................................................................................59 7.3 Oral presentations: .........................................................................................60 7.4 Conference posters ........................................................................................60 7.6 Media and press releases...............................................................................60 7.7 Anticipated publications ..................................................................................60